Fuse terminal connector

ABSTRACT

An electrical connector for the blade-type terminal of a fuse has confronting contact plates to receive the blade-type fuse terminal, an inverted U-shaped clamping member pivoted to swing about an axis transverse to the contact plates, cooperating camming parts arranged to squeeze the contact plates against the fuse terminal, and a screw at the top of the inverted &#39;&#39;&#39;&#39;U&#39;&#39;&#39;&#39; and arranged to bear against the top edges of the contact plates, to operate the camming parts.

9 United States Patent [151 3,644,880 Worth 1 Feb. 22, 1972 [54] FUSETERMINAL CONNECTOR 1,916,711 7/1933 Allgeier ....337/214 [72] Inventor:Arthur J. worth Newmk, NJ. 2,959,765 11/1960 Encson ..339/270 [73]Assignee: Federal Pacific Electric Company, Primary 9p y NewarkAttorney-Paul S. Martin [22] Filed: Nov. 28, 1969 [57 CT [21] PP 880,605An electrical connector for the blade-type terminal of a fuse hasconfronting contact plates to receive the blade-type fuse terminal, aninverted U-shaped clamping member pivoted to [52] U.S. Cl ..339/270 F,337/215, 339/274 Swing about an axis transverse to the Contact Platescooper [51] (I "Holt 9,10 ing camming parts arranged to squeeze thecontact plates [58] Fleld of Search ..339/247, 270, 273, 274, 259,against the f terminal, and a screw at the top f the Inverted 339/262;337/214, 215 U and arranged to bear against the top edges of the contact7 plates, to operate the camming parts. [56] References Cited 9 Claims,2 Drawing Figures UNITED STATES PATENTS 7 1,878,779 9/1932 Junget a1..,..339/27Q 1i PATENTEUFEB22 I972 h 3,544, 0

BV/M5WMQ ATTORNEY FUSE TERMINAL CONNECTOR The present invention relatesto connectors for blade-type terminals such as are commonly used onfuses.

An object of this invention resides in providing a new and improvedconnector having highly effective means for developing contact pressurebetween the contact plates of the connector and an inserted blade-typeterminal of a cartridge fuse. A further object of the invention residesin providing a novel connector having a means for developing highcontact pressure against an inserted blade-type terminal that is alsoeffective as a positive obstruction against possibleunintended shift ofthe terminal out of the connector but which is easily shifted out of theway when a fuse is to be removed or inserted.

A standard type of fuse is used for high currents particularly hasblade-type terminals. Connectors for such terminals conventionallyconsist of a pair of upstanding contact plates that receive a blade-typefuse terminal. In the illustrative embodiment of the invention describedin detail below terminals of this type are improved by the provision ofa clamping member having sidewalls that embrace the contact plates,cooperating cams at the outside of the contact plates and on the insideof the clamp sidewalls, arranged so that pressure is built up by motionof the clamping member away from the support of the contact plates. Ascrew extending through the bight of the clamping member is tightenedagainst the top edges of the contact plates for developingcontact-tightening cam action.

The bight is also effective for preventing a cartridge fuse from beingdriven out of the connector terminal as is caused by electrodynamicforce in some installations. Still further, when the clamping member isreleased, it pivots easily about an axis perpendicular to the contactplates to a clearance position allowing removal of one fuse andinsertion of another.

The nature of the invention will be more fully understood andappreciated, together with its further objects, novel features andadvantages, after consideration of the following description in detailof an illustrative embodiment of the invention that appears in theannexed drawings.

In the drawings:

FIG. 1 is a side view of a connector for a blade-type terminal of afuse, showing a portion of a fuse with its blade-type terminal inposition in the connector and showing a part of the connector in phantomlines in a position that it assumes when a fuse is to be removed oranother fuse is to be inserted; and

FIG. 2 is an end view of the connector of FIG. I as seen from the right.

Connectors of the type exemplified in the drawings normally form partsof an assembly having a pair of aligned connectors for the opposite endsof a cartridge fuse and in common use in a three-phase device. There arethree pairs of such connectors side by side. In the drawings, a basemember of insulation carries a supporting terminal bar 12 as of copperbearing a pair of solderless connectors 14 for external circuit wiring.A pair of contact plates 16, commonly of copper, are suitably joinedmechanically and electrically to terminal bar 12. The blade-typeterminal T of a cartridge fuse F is received and tightly secured betweencontact plates 16.

A U-shaped clamping member 18 includes a bight 20 that joins sidewalls22, 22 together. A double-headed rod 24 extends through sidewalls 22, 22and through contact plates 16, 16. The heads of the rod or shaft 24 bearagainst the outside surfaces of walls 22, 22, and prevent any tendencyof those sidewalls to spread. Shaft or rod 24 acts as a pivot thatallows the clamping member 20 to move from the solid line position inFIG. I to the position represented in phantom lines, when it isnecessary to insert or remove fuse F. When clamping member 20 is in thetilted position shown in phantom lines, it does not obstruct the spaceabove the contact plates 16. The clamping member is prevented by a stop26 from moving too far so that is remains accessible when it is to bereturned to the solid-line position indicated. Moreover, stops 26 limitthe motion of member 20 endwise of the fuse. This is important in someinstallations where there is a grounded enclosure or some otherstructure that the clamping member should not be permitted to touch.

Camming or wedge parts are provided, to act between sidewalls 22 of theclamping member 20 and contact plates 16. Each sidewall 22 includes anintegral cam part 22a which bulges toward a related contact plate 16.Upwardly and outwardly diverging cam or ramp surfaces 26a are formed onplates 26 which bear against the nearby entire outer surface of itsrelated contact plate 16. Cam plates 26 are made of steel in order to bemore durable and harder than the copper of plates 16 in performing theircam function; and by making parts 16 and 26 separate, the ramps 260 canbe formed in plates 26 by a stamping operation and yet the surface ofcontact plate 16 that engages terminal T remains undeformed.

Elongated slots 28 in sidewalls 22 of the clamping member 20 accommodatevertical motion of the clamping member so that camming parts 22a canmove upward along ramps or cam surfaces 26a for tightening the contactplates 16 against a fuse terminal T, or downward for releasing thecontact pressure.

A screw 30 is threaded through the bight of clamping member 20 andcarries a pressure foot 32 for bearing against the upper diverging edgeportions of contact plates 16. Screw 30 can rotate in pressure foot 32during tightening and loosenmg.

When a fuse terminal has been inserted and contact pressure is to bedeveloped, the clamping member 20 is moved to the position illustratedin solid lines in FIG. 1. Screw 30 is then tightened so as to drivepressure foot 32 against the upper edges of contact plates 16. Thistightening of the screw has the effect of driving clamping member 20upward, thereby driving cam portions 22a .upward along the divergingsurfaces of ramps or cam parts 26a. In the positions of the partsillustrated, cam parts 22a develop enormous pressure forcing contactplates 16 toward each other. The cam parts act on contact plates 16 mostdirectly at a point midway between the top and bottom edges of the fuseterminal T. The buildup of the cam force tends to spread the sidewall 22of the clamping member 20, but the double headed pin 24 prevents anysuch spreading motion. The shape of pressure foot 32, bearing down onthe edge portions of contact plates 16 as shown, provides a smallcomponent of force acting on the contact plates to augment the contactpressure built up by the camming structure described. More important,foot 32 provides a reaction point for screw 30, and it closes off thepath that terminal T sometimes tends to move because of electrodynamicforces tending to blow a fuse out of its terminal connectors underadverse conditions in some installations. When a fuse is to be removedand replaced, screw 30 is turned back enough to raise foot 32 so as toallow clamping member 20 to swing to the broken line position of FIG. 1.Stop 26 holds member 26 in a partly raised position, to be sure it willbe easily accessible when it is to be returned to the solid-lineposition. As a matter of detail, two stops 26b are provided so thatduplicate parts 26 can be used at the opposite sides of the connector.

It is evident that the novel concepts in the illustrative embodiment ofthe invention are subject to a latitude of change and may be utilized invarious applications and therefore the invention should be construedbroadly in accordance with its full spirit and scope.

I claim:

1. An electrical connector for blade-type terminals of fuses, comprisinga supporting terminal bar, a pair of confronting contact platesupstanding from said terminal bar and spaced apart for receiving ablade-type terminal, and means for developing contact pressure of saidcontact plates against an inserted blade-type terminal, said last-namedmeans including a U-shaped clamping member having a bight joining a pairof sidewalls between which said contact plates are received, said bightoverlying the upper edges of the contact plates remote from saidsupporting terminal bar, cooperating cam means acting between at leastone of said contact plates and the corresponding one of said sidewallsand acting primarily along an imaginary line passing approximatelythrough the center of the fuse-terminal-engaging areas of the contactplates for increasing the clamping force of said plates as said U-shapedmember is shifted in the direction away from said terminal bar, andmeans for driving said bight and said upper edges of said contact platesapart for thereby forcing said contact plates toward each other.

2. An electrical connector in accordance with claim 1 wherein saidsidewalls extend to a level below the space normally occupied by aninserted fuse terminal, further including means for restraining the endsof said sidewalls remote from said bight against spreading when saidmeans for developing contact pressure is operated.

3. An electrical connector for blade-type terminals of fuses, comprisinga supporting terminal bar, a pair of confronting contact platesupstanding from said terminal bar and spaced apart for receiving ablade-type terminal, and means for developing contact pressure of saidcontact plates against an inserted blade-type terminal, said last-namedmeans including a Ushaped clamping member having a bight joining a pairof sidewalls between which said contact plates are received, said bightoverlying the upper edges of the contact plates remote from saidsupporting terminal bar, cooperating cam means acting between at leastone of said contact plates and the corresponding one of said sidewallsand effective to increase the clamping force of said plates as saidU-shaped member is shifted in the direction away from said terminal bar,and means for driving said bight and said upper edges of said contactplates apart for thereby forcing said contact plates toward each otherand a shaft extending through openings in said sidewalls and saidcontact plates, said shaft being fo rmed for preventing spreading ofsaid sidewalls away from each other and said openings accommodatingdisplacement of said U- shaped member when said means for developingcontact pressure is operated, said shaft constituting a pivotaccommodating tilting motion of said U-shaped member away from itsposition overlying said upper edges of said contact plates for allowingremoval of a blade-type terminal from the space between said contactplates.

4. An electrical connector in accordance with claim 3 wherein saidsidewalls have slots for receiving said shaft, the

slots being elongated for accommodating motion of the U- shaped membertoward and away from said supporting terminal bar. v

5. An electrical connector in accordance with claim 3 including a fixedstop with which said U-shaped member cooperates when pivoting away fromsaid overlying position.

6. An electrical connector in accordance with claim 1 includingscrew-threaded means in said bight and having a bearing foot cooperablewith said upper edges of said contact plates for applying pressure tosaid upper edges when said contact pressure developing means isoperated.

7. An electrical connector in accordance with claim 1 wherein said cammeans includes a pair of formations opposite the approximate center ofthe fuse-terminal receiving space between said contact plates andprojecting from said sidewalls inward towards said contact platesrespectively, and includes upward divergent cam elements cooperable withsaid projecting formations, for developing contact pressure asaforesaid.

8. An electrical connector in accordance with claim 7 wherein saiddriving means includes a screw threaded through said bight and a bearingplate extending across the upper edges of said contact plates and acrossthe space therebetween for causing contact pressure to develop as saidscrew is operated to drive said bight away from the upper edges of saidcontact plates and preventing removal of a blade-type terminal from thespace between said contact plates.

9. An electrical connector in accordance with claim 7 including a shaftextending between portions of said sidewalls remote from said bight forpreventing spreading thereof when contact pressure is developed betweensaid contact plates and a blade-type terminal fuse, said contact plateshaving an opening elongated in the direction from said supportingterminal bar toward said upper edges of the contact plates, said shaftbeing received in said opening and being thus movable when contactpressure is being developed.

1. An electrical connector for blade-type terminals of fuses, comprisinga supporting terminal bar, a pair of confronting contact platesupstanding from said terminal bar and spaced apart for receiving ablade-type terminal, and means for developing contact pressure of saidcontact plates against an inserted blade-type terminal, said last-namedmeans including a U-shaped clamping member having a bight joining a pairof sidewalls between which said contact plates are received, said bightoverlying the upper edges of the contact plates remote from saidsupporting terminal bar, cooperating cam means acting between at leastone of said contact plates and the corresponding one of said sidewallsand acting primarily along an imaginary line passing approximatelythrough the center of the fuse-terminalengaging areas of the contactplates for increasing the clamping force of said plates as said U-shapedmember is shifted in the direction away from said terminal bar, andmeans for driving said bight and said upper edges of said contact platesapart for thereby forcing said contact plates toward each other.
 2. Anelectrical connector in accordance with claim 1 wherein said sidewallsextend to a level below the space normally occupied by an inserted fuseterminal, further including means for restraining the ends of saidsidewalls remote from said bight against spreading when said means fordeveloping contact pressure is operated.
 3. An electrical connector forblade-type terminals of fuses, comprising a supporting terminal bar, apair of confronting contact plates upstanding from said terminal bar andspaced apart for receiving a blade-type terminal, and means fordeveloping contact pressure of said contact plates against an insertedblade-type terminal, said last-named means including a U-shaped clampingmember having a bight joining a pair of sidewalls between which saidcontact plates are received, said bight overlying the upper edges of thecontact plates remote from said supporting terminal bar, cooperating cammeans acting between at least one of said contact plates and thecorresponding one of said sidewalls and effective to increase theclamping force of said plates as said U-shaped member is shifted in thedirection away from said terminal bar, and means for driving said bightand said upper edges of said contact plates apart for thereby forcingsaid contact plates toward each other and a shaft extending throughopenings in said sidewalls and said contact plates, said shaft beingformed for preventing spreading of said sidewalls away from each otherand said openings accommodating displacement of said U-shaped memberwhen said means for developing contact pressure is operated, said shaftconstituting a pivot accommodating tilting motion of said U-shapedmember away from its position overlying said upper edges of said contactplates for allowing removal of a blade-type terminal from the spacebetween said contact plates.
 4. An electrical connector in accordancewith claim 3 wherein said sidewalls have slots for receiving said shaft,the slots being elongated for accommodating motion of the U-shapedmember toward and away from said supporting terminal bar.
 5. Anelectrical connector in accordance with claim 3 including a fixed stopwith which said U-shaped member cooperates when pivoting away from saidoverlying position.
 6. An electrical connector in accordance with claim1 including screw-threaded means in said bight and having a bearing footcooperable with said upper edges of said contact plates for applyingpressure to said upper edges when said contact pressure developing meansis operated.
 7. An electrical connector in accordance with claim 1wherein said cam means includes a pair of formations opposite theapproximate center of the fuse-terminal receiving space between saidcontact plates and projecting from said sidewalls inward towards saidcontact plates respectively, and includes upward divergent cam elementscooperable with said projecting formations, for developing contactpressure as aforesaid.
 8. An electrical connector in accordance withclaim 7 wherein said driving means includes a screw threaded throughsaid bight and a bearing plate extending across the upper edges of saidcontact plates and across the space therebetween for causing contactpressure to develop as said screw is operated to drive said bight awayfrom the upper edges of said contact plates and preventing removal of ablade-type terminal from the space between said contact plates.
 9. Anelectrical connector in accordance with claim 7 including a shaftextending between portions of said sidewalls remote from said bight forpreventing spreading thereof when contact pressure is developed betweensaid contact plates and a blade-type terminal fuse, said contact plateshaving an opening elongated in the direction from said supportingterminal bar toward said upper edges of the contact plates, said shaftbeing received in said opening and being thus movable when contactpressure is being developed.